I acquired a 62" Thunderhorn II longbow 45@ 28 in a trade recently and it came with full length Gold Tip Traditional Hunter arrows marked 75/95 300. I have shot them a little bit with different weight field tips and 175 grain tips seem to be the best. Still the arrows show a little bit stiff, this is not bare shaft mind you. My question is should I try to go down in spine to 55/75 or should I try a heavier weight tip/ broadhead? There is not a bow shop closer than an hour drive from where I live so I would have to order online. Just looking for recommendations from the brain trust on the green screen.
Thanks in advance for any and all advice!
Grits

Most likely too stiff, depending on the arrow length as well, my Thunderhorn Heartstopper and A&H are both 56lbs at 29, 30 inch 400 Gold Tip trads, with 200 grain total up front are a hair on the weak side, but work well fletched, you may be able to increase 50 to 75 more up front and get away with it, but my guess is 400 spine, with at least 200 up front

You can make it work but it'd be a pain in the butt. Your arrows are probably 31" , if so, I'm thinking you'd need around 275 grains with the standard 16 grain insert. So if you can find a 100 grain insert your 175 bh would get you close. The problem with going down to a 500 spine is its really hard to build arrow weight with a shaft that is really close. I would go to a 400 spine and tune it out from there. Just me though.

300 spine deflection correlates to nearly 90# spine.. 500 is around 50 spine. I draw 30" and can shoot either 500 or 400 if my bows measure 45@28. Carbons recover so much more quickly than any other material. I have seen folks shoot. 600 arrows with 175 grains up front and shoot bullet holes with 45@28. Each person is different but I wouldn't even shoot 300 spine out of a 70# compound.

Thanks for the advice guys.
A little more info that I should have included earlier. I draw a about 28.5, I would like to keep using my Zwikey's that are 135g and use full length carbon arrows since there is not a bow shop anywhere close to get arrows cut. I have been advised to try to keep my arrows at around 10 gpi. The bow is cut past center also.

Thanks for the advice guys.
A little more info that I should have included earlier. I draw a about 28.5, I would like to keep using my Zwikey's that are 135g and use full length carbon arrows since there is not a bow shop anywhere close to get arrows cut. I have been advised to try to keep my arrows at around 10 gpi. The bow is cut past center also.

FYI, if you do need to get arrows cut Madisonville isn't too far from you. Hit Shawn up at Archery World. He can cut your arrows. Also, I have some 3555's you can try and I'm in Crockett. I shoot 5575's in my 50 lb bow full length with 145 gr tips. I think 7595's may be a tad stiff for your set up.